1. Field of the Invention
The present invention relates to a pneumatic tire, and more specifically relates to a pneumatic tire that achieves a high level of performance in both steering stability performance on dry road surfaces and steering stability performance on wet road surfaces.
2. Description of the Related Art
In recent years, along with enhanced performance of vehicles, a high level of performance in both steering stability performance on dry road surfaces and steering stability performance on wet road surfaces when driving at high speed has become strongly desired for pneumatic tires.
Guaranteeing drainage by providing many lug grooves and sipes on a tread surface of a tire is normally performed as a method for improving steering stability performance on wet road surfaces. However, there is the problem that it is difficult to guarantee steering stability on dry road surfaces by such a method since a rigidity of land portions formed on the tread surface decreases.
In order to achieve a high level of both steering stability performance on dry road surfaces and steering stability performance on wet road surfaces, which have an opposing relationship, many suggestions have heretofore been made concerning tread pattern structures (for example, refer to PCT International Publication WO 2005/32855 and Japanese Patent Publication (A) No. 2008-273451).
However, it has become difficult to achieve a high level of both steering stability performance on dry road surfaces and steering stability performance on wet road surfaces when driving at high speed with conventional tread pattern structures due to a gradual increase in demand for increasing vehicular speed following advances in enhanced performance of vehicles and road maintenance in recent years, and further improvement is thus desired.